Thermosensitive recording materials generally include an image forming layer situated on a substrate. The image forming layer includes a thermoresponsive dye, which upon heating changes color to produce a visible image or marking on the thermosensitive recording material. An image or a marking may be formed on a thermosensitive recording material using a printer with a thermal head, a thermal pen, laser light, or in some instances, friction across the material will generate enough heat to produce a mark or an image.
Some thermosensitive recording materials include an insulating layer, which may employ voided particles to provide insulating properties to the thermosensitive recording material. Insulating layers may provide a thermosensitive recording paper with improved print density and clearer printed images. Voided particles typically have a single void entirely encapsulated by a polymer shell.
Multi-voided particles have also been employed in the art for use in insulating layers. U.S. Pat. Pub. No. 2002/0123425 discloses a thermosensitive recording material with a first layer that includes multi-voided particles. Suitable multi-voided particles are described as being prepared from a core-shell emulsion polymerization process in which the core polymer contains a copolymerized ester functional group-monomer, such as methyl acrylate, methyl methacrylate, and vinyl acetate, which may be hydrolyzed to form multiple voids within the particle when dried.
Presently there is a need in the art to prepare thermosensitive recording materials with improved insulating properties.